Top block lifting with back block loading control

ABSTRACT

The mold includes a pair of side blocks between which are engaged top, bottom and end inner blocks to define a casting cavity. The top block is moved into engagement with an end block by screw jacks driven by a motor with a spring provided between one of the screws and the top block to accommodate thermal expansion. Load sensing means are provided to shut down the motor after a particular load between the top and an end block has been achieved.

United States Patent Peck 1 July 11,1972

[ TOP BLOCK LIFTING WITH BACK 3,286,973 11/1966 Sylvester ..249/82 BLOCK LOADING CONTROL- 3,340,926 9/1967 Sylvester 164/323 [72] Inventor: Richard O. Peck, Elk Grove Village. Ill. Primary Examiner R-oben D Baldwin [73] Assignee: AMSTED I d t i Incorporated, Attorney-Walter L. Schlegel, Jr. and Russell W. Pyle Chicago, lll. 22 Filed: Aug. 24, 1970 [57] ABSTRACT The mold includes a pair of side blocks between which are en- [211 Appl' 66499 gaged top, bottom and end inner blocks to define a casting cavity. The top block is moved into engagement with an end [52] U.S. Cl ..249/82, 254/ 103 blo k by screw jacks driven by a motor with a spring provided [51] Int. Cl. ..B29c 1/16 between one of the screws and the top block to accommodate [58] Field of Search ..249/82, 158, 162; 164/323; thermal expansion. Load sensing means are provided to shut- 318/12, 14, 15, 160; 254/98, 103 down the motor after a particular load between the top and an end block has been achieved.

[56] References Cited 2 Claims, 3 Drawing Figures UNITED STATES PATENTS 2,134,829 11/1938 McWane ..249/82 S wwaa twig/1' PATENTEDJUL 1 1 m2 Inventor: Richard O. Peck By: mwfl TOP BLOCK LIFIING WITH BACK BLOCK LOADING CONTROL The invention relates to improvements in permanent slab molds and more particularly to improvements in a pennanent slab mold having a plurality of cooperating parts.

The mold herein referred to is of the type described in US. Pat. No. 3,340,926, which is normally filled from the bottom by pressure casting. In general, the mold includes a pair of opposed side blocks, and a plurality of inner blocks engaged between the side blocks to define a casting cavity. In the mold disclosed, the inner blocks include a top block, one end of which is clamped against an end block. Various problems caused by thermal expansion of the end block have been encountered, making control of the clamping force of the top block against the end block difficult to control. Excessive force between the two blocks causes bending or distortion of the end block and may cause damage thereto.

Accordingly, an object of the present invention is to provide means for accurately controlling the clamping force between intergaged inner parts of the aforesaid mold, notwithstanding thermal expansion of said parts relative to one another.

Other objects will become apparent from the following description and appended claims, taken in connection with the accompanying drawing, wherein:

FIG. 1 is a perspective view of a portion of a permanent slab mold that incorporates features of the presently described invention;

FIG. 2 is an isolated vertical sectional view of the spring package shown in FIG. 1; and

FIG. 3 is a partial vertical sectional view of a screw jack having load sensing means, which is used in connection with the arrangement shown in FIG. 1.

Referring in greater detail to FIG. 1, a portion of a slab mold having one of the side blocks removed is shown. The mold includes a pair of opposed graphite side blocks, one of which 10, is shown held in a flask 1 1, and a plurality of inner graphite or metal blocks, including a bottom block 12, a forward end block 14, a rear end block 16, and a top block 18. The inner blocks 12, l4, l6 and 18, are clamped between the side blocks to define a casting cavity 20. The front end block 14 is slightly spaced from one end of the bottom block 12 and from the top block 18 to define, respectively, a bottom ingate 22 for the entrance of molten metal, and a riser passage 24. Other details of the mold are unimportant to the understanding of the present invention and are omitted for the sake of clarity.

As shown, the lower end of the rear end block 16 rests on the upper casting surface 26 of the bottom block 12, and the upper end of said end block is engageable with the lower casting surface 28 of the top block 18. Means are provided for lowering and raising the top block 18 into and out of engagement with the rear end block 16, said means comprising a motor 30 having respective oppositely extending shafts 32 and 34 connected to respective gear boxes 36 and 38, said gear boxes being connected by respective shafts 40 and 42 to respective screw jacks 44 and 46 located near opposite ends of the top block 18, said screw jacks being operative to drive respective screws 48 and 50 connected to the top block. The foregoing motor, shafts, gear boxes and screw jacks are are I mounted on supports, such as 52, secured to one of the side block flasks 11.

The lower end of the screw 48 nearest the riser passage 24 is pivotally connected to the top block 18 at 54. The lower end of the screw 50 nearest the rear end block 16 is pivotally connected to a disk 56, which is part of a spring package 58 best illustrated in FIG. 2. The spring package 58 comprises a hollow cylindrical member 60 secured to the top of the top block 18, said member having a circular recessed area 62 near the top thereof in which the disk is received, said disk being larger than the internal bore of said cylindrical member,- so as to be limited in travel to the height of the circular recess. Spring means, such as a helical spring 64 is provided within the cylindrical member 60 and extends between the disk 56 and an up r surface of the top block 18.

ad sensing means 15 provided in the screw jack 46 located nearest the rear end block 16, said screw jack being illustrated in detail in FIG. 3. The screw jack includes a housing 66 in which is located a worm gear 68 connected to the driven shaft 42 shown in FIG. 1. A nut 69 is threaded over the screw 50, said nut being in vertically slidable keyed engagement with a gear 70 extending around the outer periphery of said nut. Respective upper and lower ring bearings 72 and 74 are provided above and below the nut 69 to enable free rotation of the nut. Spring means, such as a helical spring 76 extends between the top of the upper ring 72 and the internal end of the housing 66. A rod 80 extends from an upper surface of the upper ring bearing 72, through an aperture 82 in the housing 66, and terminates at or near the exterior of the housing. The rod 80 is engageable with an arm 83 connected to a normally closed limit switch 84. The other screw jack is of a similar' design, except the gear is not slidable on the nut and the rod, springs and switch are omitted.

In operation, the motor 30 is activated, causing the screw jacks 44 and 46 to become activated and lower the respective screws 48 and 50 and the top block 18. After the top block 18 has contacted the upper surface of the rear end block additional force is applied, and the continued rotation of worm gear 68 and gear 70 causes the nut 69 to move upward on the now stationary shaft 50 to compress the spring 76. At the same time, the rod moves upward into contact with the arm 83 of the switch 84, which is electrically connected to the motor 30. The switch is designed such that movement of the arm opens the circuit of the motor, thereby shutting down the motor. The spring 64 is selected from a capacity as to compensate for upward thermal expansion of the rear end block and also to compensate for-extra revolutions of the motor after the switch 84 has been opened. The spring 64 is normally partially compressed when the top block is in its final position against the rear end block.

Having thus described the invention, what is claimed is:

1. An improved permanent slab mold comprising in combination a pair of opposed side blocks, front end, rear end, top and bottom blocks engaged between the side blocks to define a casting cavity, said rear end block being engageable between said top and bottom blocks, a screw mounted for supporting said top block and for bringing said top block into engagement with said rear end block, spring means interposed between said screw and said top block for accomodating relative thermal expansion between said rear end block and said top block, motor means operatively connected to said screw for raising and lowering said top block, load sensing means for sensing the load between the top block and the rear end blocks, and switch means in connection with said load sensing means to shut down said motor as given load is reached.

2. An improved permanent slab mold comprising in combination a pair of opposed side blocks, from end, rear end, top and bottom blocks engaged between the side blocks to define a casting cavity, said rear end block being engageable between said top and bottom blocks, a screw mounted for supporting said top block and for bringing said top block into engagement with said rear end block, spring means interposed between said screw and said top block for accomodating relative thermal expansion between said rear end block and said top block, a housing surrounding said screw and having a top wall, a nut in said housing surrounding said screw, a gear rotatably mounted in the housing, said nut being keyed to the gear for rotation therewith and for sliding axial movement relative thereto, a spring interposed between the nut and the top wall of the housing, and means for rotating said gear and nut to advance the screw until the top block contacts 7 the rear end block and the nut moves upwardly to compress the spring a predetermined amount.

* II i 

1. An improved permanent slab mold comprising in combination a pair of opposed side blocks, front end, rear end, top and bottom blocks engaged between the side blocks to define a casting cavity, said rear end block being engageable between said top and bottom blocks, a screw mounted for supporting said top block and for bringing said top block into engagement with said rear end block, spring means interposed between said screw and said top block for accomodating relative thermal expansion between said rear end block and said top block, motor means operatively connected to said screw for raising and lowering said top block, load sensing means for sensing the load between the top block and the rear end blocks, and switch means in connection with said load sensiNg means to shut down said motor as given load is reached.
 2. An improved permanent slab mold comprising in combination a pair of opposed side blocks, front end, rear end, top and bottom blocks engaged between the side blocks to define a casting cavity, said rear end block being engageable between said top and bottom blocks, a screw mounted for supporting said top block and for bringing said top block into engagement with said rear end block, spring means interposed between said screw and said top block for accomodating relative thermal expansion between said rear end block and said top block, a housing surrounding said screw and having a top wall, a nut in said housing surrounding said screw, a gear rotatably mounted in the housing, said nut being keyed to the gear for rotation therewith and for sliding axial movement relative thereto, a spring interposed between the nut and the top wall of the housing, and means for rotating said gear and nut to advance the screw until the top block contacts the rear end block and the nut moves upwardly to compress the spring a predetermined amount. 